package ts.test.test.shizhan4;

import org.apache.log4j.Logger;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Map;
import javax.servlet.http.HttpServletRequest;

public class SimpleBeanConvertor {
    private static Logger logger = Logger.getLogger(SimpleBeanConvertor.class);

    //将HTTP请求中的参数指定类型javaBean的相关属性
    public static <T> T convert(HttpServletRequest request, Class<T> targetType) throws IllegalAccessException
    , InvocationTargetException,  InstantiationException, ParseException,UnsupportedTypeException {
        //获取所有请求参数
        Map<String, String[]> params = request.getParameterMap();
        if (params.size() == 0) return null;
        //创建目标对象
        T target = targetType.newInstance();
        //获取所有方法
        Method[] allMethods = targetType.getMethods();
        if (allMethods != null && allMethods.length > 0){
            for (Method method : allMethods) {
                //仅处理setter访问器
                if (method.getName().startsWith("set")){
                    //获取参数类型
                    Class[] args = method.getParameterTypes();
                    if (args.length == 1){  //仅处理参数数量为1的setter方法
                        String paramName = method.getName().substring(3,4).toLowerCase() + method.getName().substring(4);
                        //获取参数值
                        if (params.containsKey(paramName)){
                            try  {
                                Object value = parseValue(params.get(paramName),args[0]);
                                method.invoke(target,value);
                            }catch (Exception e){
                                logger.error("参数转换错误",e);
                                e.printStackTrace();
                                throw e;
                            }
                        } else if (Boolean.class == args[0] || boolean.class == args[0]) {
                            //如果是boolean类型，则默认为false
                            method.invoke(target,false);
                        }
                    }
                }
            }
        }
        return target;
    }


    //将HTTP请求中的参数指定类型javaBean的相关属性
    private static Object parseValue(String[] value,Class type) throws
            ParseException,UnsupportedTypeException{
        if (String.class == type){
            return value[0];
        }
        if (java.util.Date.class == type){
            return new SimpleDateFormat("yyyy-MM-dd").parse(value[0]);
        }
        if (boolean.class == type || Boolean.class == type){
            return true;
        }
        if (char.class == type || Character.class == type){
            return value[0].charAt(0);
        }
        if (int.class == type || Integer.class == type){
            return Integer.valueOf(value[0]);
        }
        if (short.class == type || byte.class ==type || long.class == type || float.class == type ||
         double.class == type ){
            try {
                type  = Class.forName("java.lang." + type.getName().substring(0,1).toUpperCase()
                + type.getName().substring(1));
            } catch (ClassNotFoundException e) {
                e.printStackTrace();
            }
        }
        if(type.getName().startsWith("java.lang.") || type.getName().startsWith("java.math.")){
            try {
                return type.getConstructor(String.class).newInstance(value[0]);
            } catch (Exception e) {
                throw new UnsupportedTypeException(e);
            }
        }
        throw new UnsupportedTypeException();
    }
}
